李飞　王晓钰　李雪

摘要：基于美国环保署现行健康风险评价体系的理论、方法和实例污染场址情景构建了土壤重金属污染的多途径健康风险评价模型，而后利用MonteCarlo模拟法和敏感度分析技术初步量化研究了评价中参数不确定性的影响程度，并筛选得出相关敏感参数.结果表明：确定性评价下实例区域土壤中Cd和Ni的非致癌风险（HI）均小于1（HICd>HINi），对目标受体暂时不会造成非致癌健康风险；而Cd的致癌风险（RCd）大于1.0×10-6，已可能对目标受体造成致癌风险；在参数MonteCarlo模拟的辅助下，参数不确定性对于非致癌风险值的影响波动在0.1～0.2以内，而其引起致癌风险值的波动在1个数量级以内，实例中RCd的模拟值区间横跨1.0×10-6，可能误导决策；敏感度分析结果表明应重点对实例区域蔬菜和土壤中的Cd浓度及区域目标受体体重这3个敏感参数进行资料搜集，如此可以在有效提高风险评价可信度的同时降低不必要的预算开支.

关键词：土壤；重金属；风险评价；不确定性分析；MonteCarlo模拟

中图分类号：X820.2 文献标识码：A

Abstract：Based on USEPA framework of health risk assessment， the multi-pathway health risk assessment model was developed for heavy metals in the case soils. MonteCarlo simulation was adopted to quantitatively study the effect degree of parameter uncertainty on assessment result， and sensitive parameters were further identified by sensitivity analysis. The results without MonteCarlo simulation showed that there was no noncarcinogenic risk because of 1>HICd>HINi while it was under carcinogenic risk due to RCd>1.0×10-6. However， with the MonteCarlo simulation of selected variables， it indicated that the parameter uncertainty made the non-carcinogenic risk assessment results varying within 0.1～0.2， and the carcinogenic risk assessment results varying in the range within 1 order of magnitudes. Therefore， the parameter uncertainty made the value range of RCd span 1.0×10-6 and it was probable to mislead the corresponding decisionmaking. Sensitivity analysis indicated that the contents of Cd in case soils and vegetables， and the weight for the target receptor should be treated as sensitive variables， which were the main source of parameter uncertainty. To further improve the credibility of assessment with cost-benefit consideration， data of the sensitive variables should be preferentially gathered.

Key words：soils；heavy metals；risk assessment；uncertainty analysis；MonteCarlo simulation

重金属是一类具有富集性，并很难在环境中降解的有毒污染物[1].由于土壤与水体、大气等环境介质有着密切关系[2]，土壤重金属污染已经引起了公众的广泛关注，并且近年来多起公众污染事件与土壤重金属污染有关[3-4].土壤重金属污染健康风险评价作为国际广泛认可的污染预防和修复决策的辅助工具，在当下中国有着重要的现实意义.近年来，有一些学者基于健康风险……